Temp Gauge Pegged On Hot

[RBeach]

My temperature gauge is pegged all the way on high when truck is on, even when first started.

It is not a cooling issue, because when I hooked my scanner up to it and get my live readings, the temperature is in normal operating range.

If it helps, the oil pressure gauge did the same thing for about 2 weeks, but is now working fine.

I pulled the instrument cluster out to make sure the electrical connections were seated properly, and they all are.

Any suggestions?

[MagicRat]

What year is the truck?

My first thought is the gauge sender wire, sender or circuit is shorting-out to ground somewhere. Try unplugging the temp sender wire and see if there is any change.

[RBeach]

It is a 97 with the 4.2 engine.